Thin-film optical voltage sensor for voltage sensing

Patent metadata

Field	Value
Publication number	US-12339300-B2
Application number	US-202217893068-A
Country	US
Kind code	B2
Filing date	Aug 22, 2022
Priority date	Sep 3, 2021
Publication date	Jun 24, 2025
Grant date	Jun 24, 2025

Abstract

The following relates generally to optical voltage sensing, and in particular to optical voltage sensing of power grids and of a subject body. For example, some embodiments include an optical resonator comprising: (i) a top electrode layer, (ii) a piezoelectric layer, and (iii) a substrate. A light source may illuminate the optical resonator of the voltage sensor with light comprising an incident optical power at an input wavelength, where the input wavelength is offset from a resonant wavelength of the optical resonator by a baseline voltage. The applied voltage may then be measured by measuring a reflected or transmitted light power.

First claim

The invention claimed is:

1. A method of measuring a voltage, the method comprising:
applying a voltage to an optical resonator of a voltage sensor, the optical resonator including (i) a top electrode layer, (ii) a piezoelectric layer, and (iii) a substrate;
illuminating, with a light source, the optical resonator of the voltage sensor with light including an incident optical power at an input wavelength, wherein the input wavelength is offset from a resonant wavelength of the optical resonator at a baseline voltage; and
measuring the applied voltage by measuring a reflected light power reflected from the illumination by the optical resonator;
wherein the measuring of the applied voltage occurs by determining a change in reflectance of the optical resonator caused by the applied voltage; and
wherein the determining the change in reflectance includes determining the change in reflectance based on: (i) the incident optical power, (ii) the measured reflected light power, and (iii) a reflectance of the piezoelectric layer at the baseline voltage.

2. A method of measuring a voltage, the method comprising:
applying a voltage to an optical resonator of a voltage sensor, the optical resonator including: (i) a top electrode layer, (ii) a piezoelectric layer, and (iii) a substrate;
illuminating, with a light source, the optical resonator of the voltage sensor with light including an incident optical power at an input wavelength, wherein the input wavelength is offset from a resonant wavelength of the optical resonator at a baseline voltage; and
measuring the applied voltage by measuring a reflected light power reflected from the illumination by the optical resonator;
wherein the measuring the applied voltage occurs by:
determining a reflectance of the optical resonator at the applied voltage based on: (i) the incident optical power, and (ii) the measured reflected light power;
determining a change in reflectance of the optical resonator from: (i) a baseline reflectance of the optical resonator at a baseline voltage to (ii) the determined reflectance of the optical resonator at the applied voltage; and
determining the applied voltage based on the determined change in reflectance of the optical resonator.

3. A method of measuring a voltage, the method comprising:
applying a voltage to an optical resonator of a voltage sensor, the optical resonator including: (i) a top electrode layer, (ii) a piezoelectric layer, and (iii) a substrate;
illuminating, with a light source, the optical resonator of the voltage sensor with light including an incident optical power at an input wavelength, wherein the input wavelength is offset from a resonant wavelength of the optical resonator at a baseline voltage; and
measuring the applied voltage by measuring a reflected light power reflected from the illumination by the optical resonator;
wherein the measuring the applied voltage occurs by:
determining a reflectance of the optical resonator at the applied voltage based on: (i) the incident optical power, and (ii) the measured reflected light power;
determining a change in reflectance of the optical resonator from: (i) a baseline reflectance of the optical resonator at a baseline voltage to (ii) the determined reflectance of the optical resonator at the applied voltage; and
determining the applied voltage based on: (i) the determined change in reflectance of the optical resonator, and (ii) a sensor gain calculated based on:
an amplitude of a resonant dip of a reflectance curve of the piezoelectric layer;
a quality factor of the optical resonator;
a thickness of the optical resonator;
thickness mode piezoelectric strain coefficient of the piezoelectric layer;
a refractive index of the piezoelectric layer; and
a Pockels coefficient of the piezoelectric layer.

4. A method of measuring a voltage, the method comprising:
applying a voltage to an optical resonator of a voltage sensor, the optical resonator including: (i) a top electrode layer, (ii) a piezoelectric layer, and (iii) a substrate;
illuminating, with a light source, the optical resonator of the voltage sensor with light including an incident optical power at an input wavelength, wherein the input wavelength is offset from a resonant wavelength of the optical resonator at a baseline voltage; and
measuring the applied voltage by measuring a reflected light power reflected from the illumination by the optical resonator;
wherein the input wavelength is a wavelength that is a steepest point of a reflectance curve of the piezoelectric layer.

5. The method of claim 1 , wherein the input wavelength is determined according to a full-width-half max (FWHM) property of a reflectance curve of the piezoelectric layer.

6. The method of claim 1 , wherein the piezoelectric layer has a thickness mode piezoelectric strain coefficient of greater than 50 pm/V.

7. The method of claim 1 , wherein the piezoelectric layer has a Pockels coefficient of greater than 50 pm/V.

8. The method of claim 1 , wherein the optical resonator further includes a first mirror on a first side of the piezoelectric layer, and a second mirror on a second side of the piezoelectric layer.

9. The method of claim 8 , wherein the first mirror and the second mirror each include alternating layers of silicon dioxide (SiO 2 ) and amorphous silicon (Si).

10. The method of claim 8 , wherein the first mirror and the second mirror each include a first layer including a first material with a first refractive index, and a second layer including a second material with a second refractive index, wherein the first refractive index is different than the second refractive index.

11. The method of claim 1 , wherein the optical resonator further includes:
a first plurality of electrodes positioned on a top side of the piezoelectric layer, wherein the first plurality of electrodes is transparent;
a second plurality of electrodes positioned on a bottom side of the piezoelectric layer;
a first mirror positioned on the first plurality of electrodes, the first mirror including a first layer with a first refractive index, and a second layer with a second refractive index, wherein the first refractive index of the first mirror is different than the second refractive index of the first mirror; and
a second mirror positioned on the second plurality of electrodes, the second mirror including a first layer with a first refractive index, and a second layer with a second refractive index, wherein the first refractive index of the second mirror is different than the second refractive index of the second mirror.

12. The method of claim 1 , wherein the optical resonator has a diameter of between 15 micrometers and 25 micrometers.

13. The method of claim 1 , wherein the piezoelectric layer includes: barium titanate (BTO), potassium sodium niobate (KNN), bismuth ferrite (BFO), or zirconate titanate (PZT).

14. An optical voltage sensor, comprising:
optical resonator includes: (i) a top electrode layer, (ii) a piezoelectric layer, and (iii) a substrate; and
one or more processors configured to:
determine a reflected light power created by light incident on the optical resonator, the light incident on the optical resonator including an incident optical power at an input wavelength, wherein the input wavelength is offset from a resonant wavelength of the optical resonator; and
measure, based on the reflected light power reflected from the optical resonator, an applied voltage applied to the optical resonator;

wherein the optical resonator further includes a backside aluminum layer; and
wherein the piezoelectric layer is positioned on a top of the subst

Assignees

• Univ California
• Chan Zuckerberg Biohub Inc

Inventors

• Maharbiz Michel M
• Edmunds Jordan
• Sonmezoglu Soner

Classifications

• H10N30/302

  Sensors · CPC title

• G01R15/247

  Details of the circuitry or construction of devices covered by G01R15/241 - G01R15/246 · CPC title

• H10N30/853

  Ceramic compositions · CPC title

• A61B5/0031

  Implanted circuitry · CPC title

• A61B5/24

  Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof · CPC title